I just tried out a new free photo editing software program. Picnik is a web based software program. It was fast and easy to use. I've been using picasa and it works just fine. I tried paint.net a few years ago (liked it). I would also like to try photoscape. I don't do anything fancy with my photos. I usually deal in brightness (fill light), contrast, and colors. The important thing to me is that the software be easy to use.
Here's a picture you might recognize, but I did a little work on it in Picnik:
What do you use for your photo editing software?